JPH1038024A - Rubber laminated structure as seismic isolation means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax a tensile stress and stress concentration affected to the laminated rubber of a rubber laminated body by a tensile force and avoid the breaking off of the laminated rubber by installing a means for relaxing a stress by a tensile force added to the rubber laminated body at an earthquake generation time on a flange plate. SOLUTION: When the rigidity of a flange plate 1 is different at a compression area and a tension area, a tensile force is comparatively small and a large displacement is needed until a piled rubber reaches a tension yield. But, as the flange plate 1 is deformed, a stress transmitted to a rubber is not uniform and a stress concentration is generated on a rubber end part. For example, a slit 5 is formed to disperse this stress concentration. This slit 5 is formed near each bolt hole 10 formed on the periphery surface of the flange plate 1 and on the side surface of the bolt hole 10 faced to the rubber laminated body direction. Thereby, the stress concentration generated by the tensile force at the periphery of the bolt of the flange plate 1 is dispersed and the stress can be relaxed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber laminated structure as seismic isolation means comprising a rubber laminated body for seismic isolation and a flange plate for fixing a building and a foundation.

[0002]

2. Description of the Related Art In recent years, interest in earthquakes has increased, and accordingly, various devices have been devised to protect buildings from disasters caused by earthquakes. One example is a seismic isolation method for buildings, for example, building. The mainstream of this seismic isolation method is a method of supporting a building with bearings in which steel plates and rubber plates are laminated on each other. This method has been widely applied and its results are being recognized.

However, the laminated rubber used as the seismic isolation device has a compression force of 100 to 200 K with respect to a vertical compressive force.
Although it has a proof stress of gf / cm ² or more, it yields and breaks at a tensile strength of 20 kgf / cm ² or more. For this reason, it is necessary to design so that tensile force does not act,
This is one of the constraints for the seismic isolation method.

[0004]

An object underlying the present invention is a rubber laminate used in the seismic isolation method of the type described at the outset, wherein the tensile force exerted on the laminated rubber of the rubber laminate by a tensile force. An object of the present invention is to provide a seismic isolation rubber laminate in which stress and stress concentration are alleviated, and thus breakage of the laminated rubber is also avoided.

[0005]

According to the present invention, the above object is achieved by providing a flange plate with a means for reducing a stress caused by a tensile force applied to the rubber laminate when an earthquake occurs. As the above means, in the present invention, a slit is formed in the flange plate to reduce the concentration of stress due to tensile force. Further, in the present invention, as the above means, a tensile force is applied to the flange plate. Is formed to alleviate the concentration of stress caused by the stress.

The present invention will be described in detail with reference to the accompanying drawings.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the concept underlying the technology of the present invention will be described. FIG. 1 and FIG. 2 show the dynamics of these forces on the laminated rubber when a compressive force D and a tensile force Z act on the laminated rubber when a rubber laminated structure is used as the seismic isolation means. Behaved.

As shown in these figures, the mechanical properties in the vertical direction of the laminated rubber 3 'of the rubber laminated structure 3 for seismic isolation differ greatly in rigidity between the compression region and the tension region. This means that the compressive force D is transmitted uniformly from the foundation concrete 4 to the laminated rubber 3 ′ via the flange plate 1, while the tensile force Z is transmitted from the foundation concrete 4 via the bolts 2 of the flange plate 1. This is due to the fact that the flange plate 1 is deformed to transmit. The behavior of the flange plate 1 due to the compression force D and the tensile force Z is shown in FIG.
And 4. If the compression region and the tension region have the same rigidity, a tensile force having the same absolute value as the compressive force due to the overturning moment is generated (see FIG. 3). When the stiffness is different, the tensile force Z is relatively small (see FIG. 4), and a large displacement is required before the laminated rubber 3 'yields in tension.

Considering the non-linear characteristic of the vertical rigidity of the laminated rubber 3 'as described above, a large displacement is required until the rubber yields tensile strength, and a margin is generated. However, since the flange plate 1 is deformed, the stress transmitted to the rubber becomes non-uniform, and stress concentration occurs at the rubber end (see the portion indicated by a circle in FIG. 5). This stress concentration may cause a crack from the rubber end of the laminated rubber 3 ', and may cause a break.

In the present invention, starting from the technical idea described above, the rigidity at the time of tension is reduced, and at the same time, dangerous stress concentration due to this tensile force (see region K in FIG. 6).
However, as a means for alleviating the occurrence in the laminated rubber, that is, for dispersing the stress concentration K, a slit 5 was formed in the flange plate 1 as shown in FIGS. The slit 5 is formed in the vicinity of each bolt hole 10 formed on the peripheral surface of the flange plate and on the side surface of the bolt hole 10 facing the rubber laminate 3 direction.

The slits 5 are advantageously formed corresponding to the number of the bolt holes 10, ie, the number of the bolts 2, as shown in FIG. By providing the slits 5 in the flange plate 1 as described above, the stress concentration K generated by the tensile force Z around the bolts 2 of the flange plate 1 is dispersed as shown in FIG. 8, and the stress can be reduced. . Therefore, it is possible to avoid breaking of the joint portion with the laminated rubber 3 'in the edge region R (FIG. 5) of the flange plate 1 when the tensile force Z is applied.

The reason why the stress concentration is dispersed and the stress is relaxed by the slit 5 is that the stress distribution generated in the rubber by the slit changes. FIG. 8 showing the bolt holes 10 and the slits 5 in a plan view shows that the stress concentration K is dispersed. That is, from this drawing, it is clearly recognized that the tensile force Z is dispersed.

FIG. 9 is a plan view showing the bolt hole 10 and the slit 5 similarly to FIG. 8, but in this case, no slit is provided and a region of stress concentration K is recognized. FIG. 1 is a sectional view taken along the line AA of FIG. 10 and FIG.
As shown in FIG. 1, according to another embodiment of the present invention, a groove 12 is formed in an annular shape on a peripheral surface of a flange plate 1 'centering on a rubber laminate 3' as a means for relaxing a stress caused by a tensile force. Have been.

In the case of the structure using the groove 12, when a tensile force is applied to the flange plate 1 ', the flange plate 1' is largely bent, so that the tensile force transmitted to the laminated rubber 3 'is relatively reduced.

[0015]

According to the present invention, in a building having a relatively high height with respect to the width or depth of the building, the conventional method is used for seismic isolation by a laminated rubber bearing when a tensile force acts during an earthquake. Although it was difficult to design such a building, the present invention made it possible to make such a building seismically isolated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a mechanical behavior of a seismic isolation rubber laminate when a compressive force is applied.

FIG. 2 is a diagram showing a mechanical behavior of a seismic isolation rubber laminate when a tensile force is applied.

FIG. 3 is a diagram showing dynamic behavior of a compressive force and a tensile force.

FIG. 4 is a diagram showing dynamic behavior of compression force and tension force.

FIG. 5 is a diagram showing a region where the tensile force is concentrated most in the rubber laminate when a tensile force is applied to the seismic isolation rubber laminated structure.

FIG. 6 is a plan view corresponding to FIG. 5, showing a stress concentration region.

FIG. 7 is a view of a flange plate according to the present invention for mitigating tensile stress for a seismic isolation rubber laminated structure.

FIG. 8 is a view showing a state of dispersion of stress concentration when a flange plate according to the present invention is used.

FIG. 9 is a diagram showing stress concentration when a conventional flange plate is used.

FIG. 10 is an illustration of a flange plate having grooves formed according to another embodiment of the present invention.

FIG. 11 is a sectional view taken along section line AA in FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Flange plate 2 Bolt 3 Rubber laminated body 3' Laminated rubber 4 Foundation concrete 5 Slit 10 Bolt hole 12 Groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Yoshida 2222 Shinmachi, Ome-shi, Tokyo Inside Zenitaka Gumi Technology Research Institute Co., Ltd. (72) Inventor Kiyoshi Eguchi 2-10-26 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industrial Co., Ltd. (72) Inventor Akira Wada 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (3)

[Claims] In a rubber laminated structure as a seismic isolation means comprising a rubber laminated body for seismic isolation and a flange plate for fixing a building and a foundation, an earthquake occurs on the flange plate (1, 1 '). A rubber laminated structure as seismic isolation means, wherein means is provided for alleviating stress concentration due to a tensile force (Z) applied to the rubber laminated body (3 '). 2. The seismic isolation means according to claim 1, wherein a slit (5) is formed in the flange plate (1) as means for reducing stress concentration due to tensile force (Z). Rubber laminated structure. 3. A groove (1) is formed in a flange plate (1 ') as means for reducing stress concentration due to a tensile force (Z).
The rubber laminated structure for seismic isolation according to claim 1, wherein 2) is formed.